Ok, spent some more time fiddling with this. I now see what you mean (code attached).
I have never read a binary file with the <> angle operator. That idea would have never have occured to me. I have always used a read() specifying the num of bytes to read as shown below. This implies that although this "angle read" appeared to work in my .jpg example, there could be some CRLF sequence in the data that would cause this .jpg read to fail. I find that interesting to know. Good point.

I guess bottom line: Don't use <> bracket when reading binary files! 

#!/usr/bin/perl

use strict;
use warnings;

my $data = <<EOF;
first
second
EOF

print "data var in text mode - this works...\n";
print "$data\n";
print "----\n";

open my $fh, '<', \$data;
binmode $fh;
my $num_bytes = read ($fh, my $buf, 20000);
print "read () binary doesn't completely work..the normal way to read 
+binary\n";
print "this is Windows machine and I don't see both CR and LF characte
+rs\n";
print "but I think that is due to Perl translation of line endings\n";
print "bytes read = $num_bytes\n"; 
print '',$buf;

print "----\n";
print "using angle operator for binary read doesn't work\n";
print "I've never tried this before and I'm not sure why\n";
print "this doesn't work - need explanation of the angle <>op.\n";
close $fh;
open $fh, '<', \$data or die "$!";
binmode $fh;
my $bdata = <$fh>;
print '',$bdata;

__END__
data var in text mode - this works...
first
second

----
read () binary doesn't completely work..the normal way to read binary
this is Windows machine and I don't see both CR and LF characters
but I think that is due to Perl translation of line endings
bytes read = 13
first
second
----
using angle operator for binary read doesn't work
I've never tried this before and I'm not sure why
this doesn't work - need explanation of the angle <>op.
first

[download]

In reply to Re^5: Error binmode() on unopened filehandle by Marshall
in thread Error binmode() on unopened filehandle by RedJeep

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